Upcoming week - July 12-18

[Andrew92]

The following post is NOT an official forecast and should not be used as such. It is just the opinion of the poster and may or may not be backed by sound meteorological data. It is NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.

This is something I have recently thought about, and am thinking about making a weekly column each Sunday. Comments and further thoughts are greatly appreciated if I should continue this - especially since I used to frequent here much more a few years ago, but a busy life has affected my presence recently.

Much has been said in some topics here about how quiet and dead the tropics are right now. There are now some beliefs that, as happens in a lot of years, this means the season will be quieter than expected. Well, I have analyzed this upcoming week over a period of the last 15 years, coupled with what is happening now, and here are some thoughts.

2010 has no active tropical depressions or tropical storms, for one. As much as some people want to say if the season is going to be active, that something must develop soon, that may not be the case. During this upcoming week, there were seven new tropical storms to develop:

Chantal in 1995
Claudette in 1997
Danny in 1997
Arthur in 2002
Danny in 2003
Unnamed storm in 2006
Beryl in 2006

That averages out to about one storm every other year, which may make one think we are overdue for such to happen. However, when taking a closer look at this sample, one may notice that five of these storms came in El Nino years, and all of these five were from frontal lows. Only Chantal in 1995 and Danny in 2003 developed from tropical waves during this upcoming week. Therefore, the best chance of new development probably comes from a frontal low during an El Nino year (which 2010 is not). Of these five, four developed just off the East Coast and struggled. The only outlier of this bunch is Danny in 1997, which formed in the GOM and became a hurricane before landfall in first the Mississippi River Delta, than in Alabama.

In fact, looking at this bunch, Danny in 1997 is only one of two storms to become hurricanes from new developments this upcoming week. Perhaps coincidentally, the other one was also named Danny, in 2003. This storm became a hurricane north of 30 degrees.

There is one other fly in the ointment, however. Emily formed into a tropical storm on the night of July 11, 2005 - essentially as the week was beginning. It would become a hurricane just before entering the Caribbean, and then a C5 south of Jamaica.

Three other storms either became a hurricane for the first time, or re-intensified into one. Bill briefly become one at a northern latitude in 1997, and Bertha in 2008 re-intensified into one east of Bermuda, as she headed northeast out to sea. The other storm to become a hurricane during this week was Claudette in 2003, in the GOM. All of these storms were C1's.

Also, only one other storm, Bertha in 1996, became at least a C2 besides Emily. And Bertha was already a hurricane when July 12 commenced.

So what does this all tell us?

Given the situation, with not even a tropical cyclone out there, it would be pretty unusual for a tropical storm to develop this upcoming week. 2010 is known not to be an El Nino year, so a frontal low is less likely to develop tropically anytime soon. And with only two tropical disturbances going on further, the odds are against development this week. And hurricane development is increasingly less likely, and if it happened, anything more than a C1 is somewhat rare and Emily appears to be a major outlier. Model forecasts also seem to confirm that development is unlikely this week.

Even in such active years as 1998, 2000, and 2004, there was no activity this upcoming week, and in fact we are ahead of all of those years' schedules. Therefore, the season is mostly certainly in its youth and the storms are likely still a-coming - one must be patient.

Finally, is this something I should do every Sunday before each upcoming week?

-Andrew92

[cycloneye]

Finally, is this something I should do every Sunday before each upcoming week?

Yes, this is great information that you can follow up by doing it every week.

[CourierPR]

Well done. Keep up the good work.

Barry

[KWT]

Yeah this is a great thread, I certainly think its something to do again mate!

Anyway I do believe that in terms of long term statistics there is a slight dip in the number of systems for the first half of July and if you think about it it makes real sense because the SAL tends to peak around this time of year.

Hopefully this great post further helps to dilute the myths some have already suggested.

[Andrew92]

Oooh, good point KWT! I hadn't thought about the SAL, but yeah it is pretty strong right now and another reason not to predict development this week. And you're right, it does seem that it peaks around this time of year, mid-to-late July or so. That's probably a key factor for why tropical waves struggle to get going around this time of year.

-Andrew92

[KWT]

What I've noticed is that in June the wave train will actually tend to be quite strong in some years in June and whilst they don't often develop at all, they do look good for a while, but then in July as the ITCZ lifts north towards cooler waters and the SAL really increases the quality of the wave train tends to decrease as the stable air flies off Africa.

[TheBurn]

Finally, is this something I should do every Sunday before each upcoming week?

Yes please!

[vbhoutex]

Most definitely as it will help you and others continue to learn about and understand the tropics and how they work.

[Portastorm]

Think this is a great idea Andrew92! Thanks for your time and efforts. A thread like this will help all of us to keep in mind the many factors involved in tropical development.

[Chacor]

Yes, please. I'm a fan of using historical statistics (as those who've seen the WPac thread in this forum can tell) and it's a good idea.

[rockyman]

I posted this on the "quiet" thread, but I think it could be appropriate here, since it shows the "week in preview". This map will be updated at 5pm today.

http://www.cpc.ncep.noaa.gov/products/p ... ghaz.shtml

[OverlandHurricane]

Sorry if I'm a little late to this, but absolutely keep this up! Excellent work!

[Stephanie]

Great work Andrew! By all means, keep up the analysis!

[Andrew92]

Thank you guys, I definitely will have one for next week then!

I've just thought about also adding the confidence to my weekly forecasts, along with evaluating the previous week. I would have rated this week as a very confident forecast - I just don't see anything or even hint of development this week and it's a terrible time climatologically!

Had I posted one for the previous week....it's a sordid story. I thought 96L, which became TD #2, would be a lot stronger than it turned out to be!

-Andrew92

[Andrew92]

Well, as the week comes to an end, I will give my evaluation. This will also be posted in my next prediction.

This past week was one in which frontal lows are more likely to develop into tropical cyclones than tropical waves. This phenomenon is also more likely to happen in an El Nino year than a year like 2010. Reliable models also did not foresee any development. Putting all these pieces together, my forecast was for no development.

Overall, not to brag, this forecast was executed very well. No tropical waves threatened to develop, and no frontal lows looked promising either. My grade for this week is an A.

July 19-25 is coming up in a bit.

-Andrew92

[cycloneye]

Andrew, for next season consider starting this very interesting work that you do on the first week of June. I am awaiting for this week's analysis.

[Andrew92]

I definitely will start sooner next year! I only thought about this a couple weeks ago, but it so far is really helping me learn.

This week's prediction is now up, too.

-Andrew92